"metric","producing_function","family","definition","formula_units","range_interpretation","reference","output_object","controlling_arg"
"n_epochs","circadian.batch","io","Number of epochs analysed in the recording","count","non-negative integer","","summary$n_epochs",""
"epoch_length_s","circadian.batch","io","Epoch length of the recording","seconds","typically 15-60 s","","summary$epoch_length_s","epoch_length"
"L5","circadian.rhythm","nonparametric","Mean activity over the least-active 5 hours of the average day","activity counts per min","non-negative; lower = deeper rest","vansomeren1999","circadian.rhythm()$L5",""
"M10","circadian.rhythm","nonparametric","Mean activity over the most-active 10 hours of the average day","activity counts per min","non-negative; higher = stronger active phase","vansomeren1999","circadian.rhythm()$M10",""
"RA","circadian.rhythm","nonparametric","Relative amplitude of the rest-activity rhythm","(M10 - L5) / (M10 + L5); unitless","0 to 1; higher = stronger rhythm","vansomeren1999","circadian.rhythm()$RA",""
"IS","circadian.rhythm","nonparametric","Interdaily stability: strength of coupling of the rhythm to the 24 h day","n*sum((xbar_h - xbar)^2) / (p*sum((x_i - xbar)^2)); unitless","0 to 1; near 1 = highly stable, < 0.3 = weak","witting1990","circadian.rhythm()$IS",""
"IV","circadian.rhythm","nonparametric","Intradaily variability: fragmentation of the rest-activity rhythm","n*sum((x_i - x_{i-1})^2) / ((n-1)*sum((x_i - xbar)^2)); unitless","0 to ~2; ~0 = smooth sine, ~2 = noisy/fragmented","witting1990","circadian.rhythm()$IV",""
"phi","circadian.rhythm","nonparametric","First-order (lag-1) autocorrelation of the hourly activity series (1 h lag)","unitless","about -1 to 1; higher = smoother, more predictable hour-to-hour","","circadian.rhythm()$phi",""
"cosinor_mesor","cosinor.analysis","cosinor","MESOR: the rhythm-adjusted mean of the fitted 24 h cosine","activity counts","non-negative","cornelissen2014","cosinor.analysis()$mesor","period"
"cosinor_amplitude","cosinor.analysis","cosinor","Amplitude: half the peak-to-trough extent of the fitted cosine","activity counts","non-negative; larger = stronger sinusoidal component","cornelissen2014","cosinor.analysis()$amplitude","period"
"cosinor_acrophase","cosinor.analysis","cosinor","Acrophase: clock time of the cosine peak (circular)","clock hours (0-24)","0 to 24","cornelissen2014","cosinor.analysis()$acrophase","period"
"cosinor_r_squared","cosinor.analysis","cosinor","Proportion of variance explained by the single cosine","unitless","0 to 1","cornelissen2014","cosinor.analysis()$r_squared","period"
"rhythm_F","rhythmicity.test","cosinor","F statistic of the zero-amplitude (no-rhythm) test","unitless","non-negative; larger = stronger evidence of a rhythm","nelson1979","rhythmicity.test()$F","period"
"rhythm_df2","rhythmicity.test","cosinor","Denominator degrees of freedom of the rhythmicity F-test","count","non-negative","nelson1979","rhythmicity.test()$df2","period"
"rhythm_p_value","rhythmicity.test","cosinor","p-value of the zero-amplitude F-test","unitless","0 to 1; < 0.05 = detectable rhythm","nelson1979","rhythmicity.test()$p_value","period"
"percent_rhythm","rhythmicity.test","cosinor","Percent of variance the single cosine explains (100 * R-squared)","percent","0 to 100","cornelissen2014","rhythmicity.test()$percent_rhythm","period"
"rhythmic","rhythmicity.test","cosinor","Whether a rhythm is detected at the 0.05 level","logical","TRUE / FALSE","nelson1979","rhythmicity.test()$rhythmic",""
"period_tau","circadian.period","period","Dominant free-running period from the Lomb-Scargle periodogram","hours","within the search band (default 18-30 h)","lomb1976","circadian.period()$tau",""
"period_peak_power","circadian.period","period","Lomb-Scargle spectral power at the dominant period","unitless","0 to 1; higher = stronger periodicity","lomb1976","circadian.period()$peak_power",""
"period_p_value","circadian.period","period","False-alarm probability of the periodogram peak (Baluev)","unitless","0 to 1; < 0.05 = significant period","baluev2008","circadian.period()$p_value",""
"period_ci_lower","period.ci","period","Lower bound of the bootstrap period confidence interval","hours","typically <= period_tau","politis1992","period.ci()$ci_lower","level"
"period_ci_upper","period.ci","period","Upper bound of the bootstrap period confidence interval","hours","typically >= period_tau","politis1992","period.ci()$ci_upper","level"
"period_ci_se","period.ci","period","Bootstrap standard error of the period estimate","hours","non-negative","politis1992","period.ci()$se","n_boot"
"chisq_period","chi.sq.periodogram","period","Dominant period from the chi-square (Sokolove-Bushell) periodogram","hours","within the search band","sokolove1978","chi.sq.periodogram()$period",""
"chisq_Qp_peak","chi.sq.periodogram","period","Peak Qp statistic of the chi-square periodogram","unitless","non-negative; above threshold = significant","sokolove1978","chi.sq.periodogram()$Qp_peak",""
"chisq_p_value","chi.sq.periodogram","period","Significance of the chi-square periodogram peak (Sidak-corrected)","unitless","0 to 1","sokolove1978","chi.sq.periodogram()$p_value",""
"dfa_alpha","fractal.dfa","fractal","Overall detrended-fluctuation scaling exponent","unitless","~0.5 = noise, ~1 = 1/f, > 1 = random-walk-like","peng1994","fractal.dfa()$alpha",""
"dfa_alpha1","fractal.dfa","fractal","Short-time-scale DFA exponent (scales below the fixed breakpoint, default 90)","unitless","interpreted as for dfa_alpha","peng1994","fractal.dfa()$alpha1",""
"dfa_alpha2","fractal.dfa","fractal","Long-time-scale DFA exponent (scales above the fixed breakpoint, default 90)","unitless","interpreted as for dfa_alpha","peng1994","fractal.dfa()$alpha2",""
"mfdfa_h2","mfdfa","fractal","Generalized Hurst exponent at q = 2 (equals the DFA exponent)","unitless","~0.5 to 1.5","kantelhardt2002","mfdfa()$alpha_dfa",""
"mfdfa_width","mfdfa","fractal","Width of the multifractal singularity spectrum","unitless","non-negative; wider = more multifractal","kantelhardt2002","mfdfa()$width",""
"mse_area","multiscale.entropy","fractal","Sum of sample entropy across scales (complexity index)","unitless","non-negative; higher = more complex","costa2002","multiscale.entropy()$area","scales"
"mse_slope","multiscale.entropy","fractal","Least-squares slope of sample entropy across scales (package trend summary)","unitless","sign indicates rising or falling complexity with scale","","multiscale.entropy()$slope","scales"
"kRA","state.transitions","phase","Rest-to-active transition rate over the LOWESS plateau","per epoch","0 to 1; typically < 0.5; higher = more fragmented rest","lim2011","state.transitions()$kRA",""
"kAR","state.transitions","phase","Active-to-rest transition rate over the LOWESS plateau","per epoch","0 to 1; typically < 0.5; higher = more fragmented activity","lim2011","state.transitions()$kAR",""
"pRA","state.transitions","phase","Overall rest-to-active rate (reciprocal mean rest-bout length)","unitless","0 to 1","danilevicz2024","state.transitions()$pRA",""
"pAR","state.transitions","phase","Overall active-to-rest rate (reciprocal mean active-bout length)","unitless","0 to 1","danilevicz2024","state.transitions()$pAR",""
"SRI","sleep.regularity.index","sleep","Sleep Regularity Index: how consistently the sleep/wake state repeats 24 h apart (requires sleep_state)","200*P - 100, where P is the fraction of epoch pairs 24 h apart in the same state; index points","-100 to 100; 100 = perfectly regular, 0 = random, higher = more regular","phillips2017","sleep.regularity.index()",""
"social_jet_lag_hours","social.jet.lag","sleep","Social jet lag: mid-sleep difference between free and work days (requires sleep_periods)","hours","typically 0 to 3; larger = greater misalignment","roenneberg2012","social.jet.lag()$social_jet_lag_hours",""
"MSW","social.jet.lag","sleep","Mid-sleep on work days","clock hours (0-24)","0 to 24","wittmann2006","social.jet.lag()$MSW",""
"MSF","social.jet.lag","sleep","Mid-sleep on free days","clock hours (0-24)","0 to 24","wittmann2006","social.jet.lag()$MSF",""
"lids_period_min","lids","sleep","Mean Locomotor Inactivity During Sleep ultradian period (requires sleep_periods)","minutes","typically ~95 to 130 min (median ~110)","winnebeck2018","lids()$mean_period_min",""
"lids_MRI","lids","sleep","Mean Munich Rhythmicity Index of the LIDS cycles (requires sleep_periods)","unitless",">=0 on the 0-100 LIDS scale; higher = stronger ultradian rhythm","winnebeck2018","lids()$mean_MRI",""
